Technical Field
This disclosure relates to an image projection apparatus.
Background Art
Image projection apparatuses that project images on a projection face (e.g., screen) are used in a wide range of fields for display to a large number of people such as presentations, conferences, lecture meetings, educational sites, and home theaters. When the image projection apparatus receives image data transmitted from an information processing apparatus such as a personal computer, a video reproduction device such as a digital versatile disk (DVD) player, an imaging device such as a digital camera, an optical image generation element (or modulation element, image generation element) generates an image based on the received image data, and then the image is projected on a projection face (e.g., screen) through an optical system including a plurality of lenses or the like.
As to the image projection apparatuses widely used in presentations, conferences, lectures, meetings, educational institutions, movie viewing, and signage for a large number of people, image quality has been enhanced. The image quality projected by the image projection apparatuses can be increased by increasing the pixel density of the image generation element, but this results in increase in the manufacturing cost of the image generation element.
When an image projection apparatus is used for projecting images, the image projection apparatus may not be set at a position in the exact front of a projection face, in which the image projection is performed from an oblique direction with respect to the projection face. In this case, since distortion occurs in the projected image, conventional image projection apparatuses have a keystone distortion correcting function for correcting the distortion. The keystone correction processing is performed for image signals (original images) input to the image projection apparatus to generate an image having a smallest image deterioration.
In the image projection apparatus that performs the pixel shift control, two images (two frames) are generated from one original image (one frame) input to the image projection apparatus before outputting the two images to the image generation element, and the generated two images (two frames) are alternately output by synchronizing with the movement of an optical element or the image generation element.
However, if the image processing of the pixel shift control is performed to the images applied with the keystone correction processing, degradation of the image quality becomes greater and visibility is reduced.